有没有更好的方法来做回调链在javascript？ [英] Is there a better way to do callback chaining in javascript?

问题描述

我写了一个回调助手，让我将多个回调组合成一个函数变量：

I wrote a callback helper, that lets me group multiple callbacks into one function variable:

function chainCallbacks() {
    var callbacks = arguments;
    return function () {
        for(var i = 0; i < callbacks.length; i++) {
            if(callbacks[i] != null) {
                callbacks[i].apply(null, arguments);
            }
        }
    };
}

这可行，但我想知道是否有任何JavaScript库相同的功能？或者甚至更好，模拟.NET事件模式的东西？

this works, but I'm wondering if there are any javascript libraries that provide the same functionality? or even better, something that simulates the .NET "event" pattern?

myEvent+=myCallback;

推荐答案

我已经修改了chainCallbacks函数。您可以在JS控制台中测试以下代码（我使用Chrome -works精细），并检查结果。

I have modified your chainCallbacks function. You can test below code in JS console (I'm using Chrome -works fine), and check the result.

var result = 0;

function a() {
        result += 5;
        console.log(result);
        _next();
}

function b() {
        result += 10;
        console.log(result);
        _next();
}

function c() {
        result += 20;
        console.log(result);
        _next();
}

function chainCallbacks() {

    var _this = this;
    var _counter = 0;
    var _callbacks = arguments;

    var _next = function() {
        _counter++;
        if(_counter < _callbacks.length) {
            _callbacks[_counter].apply(_this);
        }
    };

    _this._next = _next;

    return function() {
        if(_callbacks.length > 0) {
            _callbacks[0].apply(_this);
        }
    };
}

var queue = chainCallbacks(a, b, c);
queue();

想法很简单 - 你调用 _next（）每当你的回调函数完成执行，并且你想跳到另一个。所以你可以调用 _next（）例如。在一些jQuery动画之后，这样你将保留函数的顺序。

Idea is simple - you call _next() whenever your callback function has finished executing, and you want to jump to another. So you can call _next() e.g. after some jQuery animation as well, and this way you will preserve the order of the functions.

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